The act of trapping someone in a circle of people who then push him/her around within the circle as violently as possible, sort of like a circle of death. Particularly brutal when the victim is drunk. Gets its name from the fact that the person in the middle of the circle often gets well and truly merked. Punching, kicking, scratching, headbutting and biting are often part and parcel of a merkle circle.

Mother: Oh my god Perry what happened to you? You've got a bloody nose and a patch of hair has been ripped off your crown!
Perry: I got merkle circled three times at school today. The third time, in the changing rooms, I was butt naked.

Performing a merkle circle on unsuspecting victims is a favourite hobby of many immature chavs.